Insect eating, officially called entomophagy, is an age-old custom found throughout the world and often considered standard dietary practice. Nearly 2,000 species of insects are eaten by approximately 2.5 billion people worldwide.

We come from a long line of bug eaters. Our earliest primate ancestors were insectivores and our closest living relatives, the chimpanzees, make rudimentary tools to fish termites out of narrow tunnels in their mounds. Among the laws of Leviticus codified by the Israelites millennia ago is permission to eat "the locust after its kind, and the bald locust after its kind, and the cricket after its kind, and the grasshopper after its kind".

Roman naturalist Pliny wrote that beetle grubs were so prized that they were fattened on meal to enhance their flavour. And the German explorer Heinrich Barth wrote in his 1857 Travels and Discoveries in North and Central Africa that people who ate locusts could "enjoy not only the agreeable flavour of the dish, but also take a pleasant revenge on the ravagers of their fields".

Some of the most interesting bits on entomophagy are found in Vincent M Holt's 1885 booklet Why Not Eat Insects? Holt recognised that it would be difficult for many people to overcome squeamishness, but he also felt that with a "fair hearing", an "impartial consideration of arguments" and an "unbiased judgment", they would be persuaded to rid themselves of their "stupid prejudices" and use insects as food. To this end, he drew up menus of curried cockchafers, moths on toast, devilled chafer grubs and slug soup.

Quite simply, over centuries and across the globe, eating insects has been the norm.

In contemporary Western Europe and North America, entomophagy occupies only a tiny (but growing) culinary niche - at this point, perhaps, more curiosity than anything else. In London, the high-end department store Selfridges now sells toffee-flavoured candies and vodka-flavoured lollipops containing scorpions, worm-salt infused with chilli and agave, and oven-baked worm crisps.

Buggy fare has been available at the Audubon Insectarium in New Orleans and at entertaining educational events such as BugFest at the North Carolina Museum of Natural Sciences, Bug Bowl at Purdue University in Indiana, City of Insects at the Netherlands' Wageningen University, and Bug Fair at the Natural History Museum of Los Angeles County. Oxford University's Museum of Natural History hosted a multicourse "Grand Banquet of Rainforest Insects" to garner support for rain forest protection.

"Eating insects is, unfortunately, something that will not be of immediate interest to the majority of the people living in the West," said Marc Dennis, an artist, professor, and amateur chef who launched insectsarefood.com, a comprehensive online resource for entomophagists. "But when considering all the benefits of entomophagy, it amounts to a viable means of solving a wide range of ecological, economic and health-related issues and concerns."

Reasons to eat bugs

Indeed, novelty and fundraising are far from the only motivations for entomophagy. Today, there are one billion hungry people on the planet and that number is going to grow as population expands. Based on a medium level of average fertility, the United Nations (UN) predicts a global population of 9.3 billion people by 2050 and 10.1 billion in the next 90 years. Taking into account existing levels of malnutrition, the UN estimates that food production will need to increase by 70 percent to feed this new population.

Alongside this challenge are soaring food costs and ecological pressures. Global food prices rose sharply in 2007-2008 and have remained high since. While prices are expected to ease somewhat, they will still average 20-30 percent higher in the next decade than over the past 10 years.

Agriculture is also "the main driver of most ecological problems on the planet," said economist Jeffrey Sachs, director of Columbia University's Earth Institute. "We are literally eating awaythe other species on the planet."

Typical Western repugnance of entomophagy is cultural rather than scientific or rational. After all, other invertebrates such as certain crustaceans and mollusks are favoured culinary items.

PJ Gullan and PS Cranston , The Insects: An Outline of Entomology

Huge amounts of land, feed crops and water are required to rear livestock. Conversion of vegetable-based calories to animal-based calories is inefficient and, in a resource-constrained world, we need to think about that equation.

The livestock sector also contributes heavily to greenhouse gas emissions, causes widespread deforestation and biodiversity loss, accounts for 8 percent of global water use (mostly through irrigation for pasture and feed crops), and is probably the largest single source of water pollution. In the US, livestock alone are responsible for an estimated 55 percent of erosion and sediment, 37 percent of pesticide use, 50 percent of antibiotic use, and a third of the loads of nitrogen and phosphorus into freshwater resources.

"When the turmoil of the World War threatened to imperil the food resources of civilised nations, the question of 'substitutes' became a serious one, and, among other suggestions, experiments were urged by the eminent entomologist Dr LO Howard to ascertain the food value of insects," wrote naturalist Joseph Bequaert in 1921. His article, entitled "Insects as Food," in Natural History Magazine may again be gaining relevance as we grapple with a potentially looming nutritional and environmental crisis.

According to the UN Food and Agriculture Organization, insects have the potential to supplement the growing global demand for protein. Since insects are cold-blooded, they do not need as much feed as birds and mammals, which consume more energy to maintain their body temperatures. This means insects convert feed into protein of comparable quality to other animal meat sources much quicker and more efficiently than traditional livestock.

Insects are also a significant source of iron, zinc and vitamin A - important in light of the fact that some two billion people are deficient in zinc, one billion have iron-deficiency anaemia and vitamin A deficiency affects some 250 million people, mainly young children and pregnant women in developing countries.

Insects produce less waste, too. The proportion of livestock that is not edible after processing is approximately 30 percent for pork, 35 percent for chicken, 45 percent for beef and 65 percent for lamb. By contrast, only 20 percent of a cricket is inedible.

As an added benefit, because human physiology differs more from insects than from mammals, the chance that a pathogen will jump from a cooked insect to a human diner is smaller than the chance it will jump from another mammal to a human. The more evolutionary distance we have from a food source, the less danger there is that a disease could actually affect a human after the meal has been cooked.

Six-legged gold

Entomophagy can also indirectly increase incomes in poor communities. In Mexico, farmers who once spent money on pesticides to keep bugs off their crops have realised that by collecting and selling the insects, candy-coated or fried, they can make larger profits and reduce pesticide payments. In South Africa, approximately 9.5 billion mopane worms (emperor moth caterpillars) are harvested annually from 7,700 square miles of mopane forests. They are worth $85 million, of which approximately 40 percent goes to the collectors (primarily poor, rural women).

Unfortunately, as in all harvesting of wild creatures, overexploitation can occur. In Southern Africa, there are areas where the mopane worm has been extirpated. Tshireletso Lorraine Lucas, who studied the harvesting of mopane worms in Central Botswana, found that their numbers are declining, and that this is in part due to overharvesting, which is increasingly motivated by commerce rather than subsistence. Leah Snow Teffo of the University of Pretoria and her team, working in South Africa, have shown that the demand for edible stink bugs already exceeds supply.

One solution to the problem of overharvesting is insect farming. In Thailand, for example, approximately 20,000 farmers are engaged in raising insects. Some arthropods are already reared on an industrial scale, such as edible scorpions in China. In temperate zones, where insect rearing companies produce insects as feed or fishing bait, some growers have set up special production lines geared toward human consumption.

And, of course, raising insects appears to be slightly more humane than raising other animals. Marcel Dicke and Arnold van Huis, professors of entomology at Wageningen University, note that housing cattle, swine, or chicken in high densities causes stress to the animals, but insects, such as mealworms and locusts, naturally like to live in dense quarters and thus can be guiltlessly crowded into vertical, stacked trays or cages. Nor do bug farms have to be restricted to rural areas; they could sprout up anywhere, from a suburban strip mall to an apartment building. Enterprising gourmets could even keep a few trays of mealworms in the garage to ensure a fresh supply.

In some cases, insect harvesting could even serve as a method of biological pest control. Swarms of millions upon millions of locusts can wipe out entire crops in Africa. It would be sheer madness to ignore this flying protein or to use chemical pesticides to kill insects that are possibly more nutritious than the crops they prey on. Furthermore, cultivating and harvesting insects requires that forests be preserved, not felled. So, in the end, insect eating may result in benefits across the board: for people's stomachs and bank accounts, for local agricultural crops and forests, and for the planet.

The aversion to entomophagy among North Americans and Europeans, who do not grow up with the custom and often find it difficult or disgusting, remains one of the major challenges to its widespread adoption. Authors PJ Gullan and PS Cranston write in their bookThe Insects: An Outline of Entomology, "Typical Western repugnance of entomophagy is cultural rather than scientific or rational. After all, other invertebrates such as certain crustaceans and mollusks are favoured culinary items." Certainly, crabs, shrimps and lobsters, which are also arthropods, do not seem to elicit the same "yuck" factor in westerners.

Gullan and Cranston also argue that objections to eating insects cannot be justified on the grounds of taste or food value, since many have a nutty flavor and studies report favorably on the nutritional content of insects. We also already use many insect products to dye our foods, such as the red dye cochineal in imitation crab sticks, Campari and various candies. And no processed food is really free of insects, anyway: we already consume up to a half-kilogram of insects per year in tomato soup, apple sauce, peanut butter, chocolate, coffee and various other processed foods.

Different cultures consume different types of foods. Clearly, what is edible in one culture may not be in another. Cultural differences in food tastes are often said to have an economic or geographical basis. The anthropologist Marvin Harris has said that when people reject certain foods, there must be a logical and economic reason for doing this. According to Harris, entomophagy was taboo in cultures with protein sources that required less work, like farmed birds or cattle.

In other words, Harris felt the insect diet was less efficient and less reliable than the fish, fowl, and meat diet preferred in Europe and North America. In temperate climates, there are generally fewer edible insects, and therefore, in the past, it may have been an inefficient use of time and energy to incorporate insects into the diet. Quite simply, it may not have been worth it.

Unfortunately, westerners' fear of insect feeding can be taken to extremes and lead to ecologically, nutritionally and economically foolish behaviours. In Central Africa, missionaries often convinced local people that insect eating was disgusting - and thus persuaded them to abandon a valuable source of high-quality protein and mineral nutrition.

Insects and food security

But times change. And insect cuisine is now becoming the subject of cookbooks and the object of praise from various chefs. David George Gordon, a Seattle-based science writer, is the author of The Eat-a-Bug Cookbook: 33 Ways to Cook Grasshoppers, Ants, Water Bugs, Spiders, Centipedes, and Their Kin. According to Gordon:

"Food insects and other arthropods will find their way into our diets sooner than we have forecasted, probably in the form of 'animal protein' additives to some of our familiar foods. Raising cattle as a source of protein is untenable - studies have shown that we're already using all of the available land on our planet for farming and we simply can't boost production to keep up with the pace of population growth. For the sake of our planet, we need to start eating lower down on the food chain and we need to do it fairly soon."

Thomasina Miers, cookbook author, chef of the award-winning London restaurant Wahaca, and an avid environmentalist, feels that the global population expansion and an increasing reliance on fish and meat will put critical pressures on an already-stressed food system - a pressure that insects can help alleviate.

While insects contribute significantly to the food security and livelihoods of millions of people as a reliable source of protein, carbohydrate, vitamins, and traditional medicines, it must be remembered that entomophagy is not just a behaviour taken up as a last resort. In some countries, like Thailand, demand for edible insects increases as living standards improve.

David George Gordon, who has made a career out of educating people about edible bugs, is dismayed by events and reality television programmes that focus more on the gross-out factor, than on showing people the culinary side of insects. He feels strongly:

"We kind of like to think all these other cultures are so suffering from lack of nutrition that they eat bugs. Which is kind of like saying we eat oysters on the half shell because we need protein. This is not just about nutrition. This is legitimate comfort food in many parts of the world."

And, as Miers points out, insects are not just for the starving and the poor:

"In Mexico, insect dishes like escamoles (ants' eggs) and gusantes (roast worms) are considered real delicacies. Perhaps it is only a matter of time before culinary inventiveness and environmental necessity change our food map forever."

Dawn Starin is an honorary research associate at University College London and has spent decades conducting anthropological and ecological research in Africa and Asia. She has written both academic and non-academic articles, appearing in publications such as the New York Times, the Ecologist, the Journal of the Royal Society of Medicine, and Gastronomica, among others.

ABOUT THE AUTHOR

Dawn Starin is an honorary research associate at University College London and has spent decades conducting anthropological and ecological research in Africa and Asia. She has written both academic and nonacademic articles for several journals.